Fluid pressure motor



Jan. 28, 1936. G, KUHN 2,029,240

FLUID PRES SURE MOTOR Filed oct. 41932 2 sheets-sheet 1 lllllllllk ...lill

Jan. 2s, 193s. G, KUHN FLUID PRESSURE MOTOR Filed Oct. 4, 1932 y 2 Sheets-Sheet 2 III e III I l I I I l l I I l I ||ur||||ll lapph? l r 5 @f2 Y u Patented Jan. 28, 1936 STAT 'ATENT OFFICE Application October 4,

7 Claims.

The present invention relates to fluid pressure motors and has as a principal purpose to provide a motor wherein all the moving parts, with the Vexception of a portion of the main power transmitting element, are entirely enclosed within a single casing.

A further object ofthe invention 1s to provide a motor casing composed of complemental parts which conjointly denne power and control chambers. and fluid passages operatively connecting the various chambers so that the casing parts may be cheaply die cast. Preferably, the main portion of the motor casing is split in a plane in which the axes of the various movable elements lie.

The invention particularly contemplates a iiuid pressure motor of reciprocating type provided with reciprocating control and pilot valves and it is a further object of the invention, in its preferred form, to provide the various casing chambers or recesses with liners for the guidance of the moving parts, these liners preferably being in the form of tubes of brass or the like clamped between the casing parts.

It is a further object of the invention to provide the casing with a common exhaust chamber into which all the exhaust ports open, this chamber being formed in part by a. removable plate dening a pocket in conjunction with an exterior wall of the main casing parts.

It is a still further object of the invention to conserve space and greatly reduce the overall dmensions of the casing by p-roviding flat ribbonlike fluid passages, these passages being constituted by relatively narrow and relatively deep grooves formed in the mating casing parts and registering when the parts are brought together.

Another object of the invention is to provide a direct rectilinear connection between the power piston and pilot valve, this connection including adjustable elements so that the stroke of the power piston can readily be varied.

In the accompanying drawings I have illustrated a preferred embodiment of the invention and further description of the invention will proceed with reference to these drawings, it being understood that the embodiment to be described is merely illustra-tive and not restrictive of the invention. Other objects than those particularly mentioned above will be evident from the specific description to follow:

In the drawings:

Figure 1 is an elevation of the new motor with the cover plate, above referred to, removed in order to show the arrangement of the outlet ports.

1932, Serial No. 636,216

Figure 2 is a section on line 2-2 of Figure 1.

Figure 3 is a section on line 3--3 of Figure 4.

Figure 4 is a plan view of one of the motor parts with one of the main casing parts removed.

Figure 5 is a partial View similar to Figure 4 but showing a modied packing arrangement.

Figure 6 is a section on line 6 6 of Figure 4.

Figure 7 is an elevation of a liner for a control piston chamber.

Figure 8 is a section on line 8-8 of Figure 7.

Figure 9 is an elevation of a liner for a pilot piston chamber, and

Figure 10 is a section on line I-Ill of Figure 9.

Referring to the drawings, the casing is composed of two main complemental parts II and I2, Figures 1 to 6, these parts having contacting faces complementally recessed so that conjointly the casing parts define a number of chambers, here shown as cylindrical, operatively connected by iiuid passages. For ease of manufacture the inner face of each casing part II and I2 is substantially plane and the axes of the various cylindrical chambers lie in this plane. The parts, as will appear, can be readily die cast without the use of any cores. It will be understood that while the casing parts preferably meet in a plane, the invention is not necessarily limited in this respect. While the interior face of casing part I I has not been shown in detail, it will be understood that it is formed as an exact complement to the inner face of the part I2 as shown in Figure 4.

Referring to Figure 4, part I2 is provided with a semi-cylindrical recess I3 which receives half of a cylindrical tubular liner I4 which may conveniently be a section of brass tubing. At the top and bottom of recess I3, the liner I4 ts against shoulders I5 and I 6 which hold it against longitudinal displacement. At its upper end, part I2 is provided with a semi-cylindrical collar I'I coaxial with the recess I3, this collar projecting externally and being provided with inner and outer threads. At its medial portion, the collar is provided internally with an annular rib I8.

To one side of recess I3, part I2 is provided with a smaller semi-cylindrical recess I9 whose axis is parallel with the axis of recess I3. A relatively narrow and relatively deep groove formed in part I2 connects the upper end of recess I3 with recess I9 somewhat below the upper endv of the latter and a similar groove 2I connects the lower end of recess I3 with the lower end of recess I9. The passage 2I debouches into recess I9 a distance above the lower end of the latter equal to the distance of the end of passage 20 below the upper end of recess I9. At the top of recess I9, part I2 is provided with a relatively wide and ilat recess 22 extending transversely of recess |9 and a similar recess 23 is provided at the lower end of recess I9. In recesses 22 and 23 are provided central lugs 24 and 24 whose opposed faces are flush with the parallel planes dening the top and bottom of recess I9. A cylindrical liner- I, these being indicated at 20 and 2|', Figure 2.

Liner 25 is provided with an interrupted slot 28 on its side opposite from slots 26 and 21 and midway between the latter, slot 28 registers with a groove 29 in part I 2 which is in connection ,with an inlet chamber 3D. In Figure 2, reference numeral 29' designates the groove complemental to groove 29. Throughout the drawings, such recesses or grooves as are shown in part are designated by the primed reference numeral of the corresponding recess or groove of part I2.

Immediately below recess I9 and coaxial therewith is a semi-cylindrical groove 3| which receives a cylindrical liner 32 held against longitudinal movement by upper and lower shoulders,

Vcasing part I2 being provided with upper and lower grooves or recesses 33 and 34 at the ends of recess 3|. Between recesses 23 and 33 part I2 is provided with a recess 35 having semil cylindrical upper, lower and intermediate portions, the latter constituting a semi-annular rib separating the two former, this recess being coaxial with recesses I9 and 3|.

Immediately below recess I3 and coaxial therewith, part I2 is provided with a comparatively small semi-cylindrical recess 36 in which is disposed a liner 31, the liner being held in the recess against longitudinal movement by means of suitable shoulders as shown. Liner 31 is provided on its right hand side with upper and lower slots 38 and 39 and on its left hand side with a lcentral slot 40, these being formed as described with reference to liner 25. Slot 38 registers with one end of a groove 4| whose other end terminates in groove or recess 34, while slot 39 registers with one end of a groove 42 whose other end terminates in groove or recess 33.

A blind groove 43 terminates above recess 36 and a blind groove 44 terminates below recess 36. Slot 40 of liner 31 registers with one end of a groove 45 whose other end terminates in the inlet chamber 30.

Between recesses I3 and 36 is a coaxial recess 46 having upper, lower and intermediate semicylindrical portions, the latter dividing the two former so as to form a constriction therebetween.

It will be understood that while the liners have been described as being in position in the various recesses provided therefor, they are placed therein by separate operations upon the completion of the castings and prior to their insertion various other elements are associated therewith. The liners and associated parts will be assembled in .lar piston rod 5|.

the recesses provided therefor in one or the other of parts and I2. In Figure 4 it is assumed that they have been assembled in part I2. It will be further understood that after the liners and associated parts have been assembled in one of the casing parts, to complete the assembly, it is only necessary to lay the other casing part over the first and secure the two together.

Referring particularly to Figure 4, liner I4 has therein a main or power piston here shown as comprising a pair of oppositely cupped yicldable discs 41 and 46 clamped together between nuts 49 andl 5|) threaded on the lower end of a tubu- Washers 52 and 53 between the nuts and discs 41 and 48 constitute stiffening means for the latter. Nut 53 is in the form of a cap nut provided with a central bore 59 coaxial with piston rod 5|.

A gland nut 54 surrounds the upper end of piston rod 5I and into the upper end of the latter is threaded a screw stud or plug 55 which carries a jam nut 56 adapted to abut the upper end of the piston rod. A packing member 51 surrounds the piston rod below gland nut 54 and is circumferentially recessed at its medial portion to be engaged by the rib I 8. Both ends of the packing member are conically shaped, the upper end for compression by the gland nut and the lower end for compression by pressure existing in the liner or cylinder above the piston. l

Extending upwardly within the hollow piston rod 5| is a stem 58, the lower portion of the stem being guided in the bore 58 and the upper end being threaded and engaged by a split nut 59 which grips the stem with suiicient force to avoid its accidental displacement. On the lower end of stem 58 is formed an auxiliary control or pilot piston having thespaced enlargements 66 and 6| and above the pilot piston the stem is surrounded by a packing member 62 engageable in recess 46, the upper end of the packing member being conically shaped for compression by pressure existing below the main or power piston 41, 48. The pilot piston, comprisingV the piston portions or enlargements 66, 6|, is assembled in liner 31, to constitute a pilot valve therewith, the spacing and length of the enlargements being such that in the upper limit position of the pilot piston, portion 6|) lies between grooves 43 and 4| and portion 6| between grooves 45 and 39 so that groove 45 is in communication with groove 4| between the piston portions and groove 39 is in communication with groove 44. In the lower position of the pilot piston, groove 45 is placed in communication with groove 39 and groove 4| with groove 43.

Liner 32 has assembled therein a flexible cupped piston disc 62 clamped between nuts 63, 64 and washers Y65, 66 on the lower threaded end of a valve stem 61. A valve piston on the upper end of stem 61, and assembled in liner 25 to constitute therewith a control valve, comprises two portions 68 and 69 and between the latter and piston 62, stem 61 is Vsurrounded by a packing member 16 which is exactly the same as packing member 62 heretofore described, but inverted as regards position.

' In the illustrated upper position of piston 62, the control valve piston constituted by piston portions 68 and 69 is so positioned that portion 68 is in abutment with lug 24 and is above groove 20 so that the latter is in communication with groove 29 and inlet opening 39, portion 69 being so positioned that groove 2| is in communication with groove 23. In the lower position of the control valve piston, wherein the portion 69 abuts the lower lug 24', the inlet chamber 30 is placed in communication with groove 2I through groove 29 and groove 2l! is placed in communication with groove 22.

Grooves 22, 23, 43 and 44 are provided for exhaust purposes and their complemental grooves 22', 23', 43' and 44 have portions extending through the wall of casing part I I and debouching on the exterior thereof in a shallow recess 1I which is walled by a iiange 12 whose outer face preferably lies in a plane parallel to the plane of division of the parts II and I2. The recess flange is provided with a semi-cylindrical recess 13 provided near its inner end with a semi-annular groove 14, and an exhaust pipe 15 is disposed in the recess, the pipe having a anged end 16 engaged in groove 14. A cover plate 16 has a border portion or iiange 11 adapted to overlie flange 12, the two flanged portions being secured together as by screws 18 so that an exhaust pocket is dened. The cover plate has a recess 13 complemental to recess 13 so that the `end of tube 15 is securely clamped between the two parts.

Parts I I and I2 are provided with complemental semi-cylindrical recesses 19 and 19', similar to recesses 13 and 13 just described, in which is engaged the flanged end of an inlet pipe 8e. Parts II and I2 are provided with peripheral flanges I I and I2' provided with apertures which register when the parts are brought together, bolts or rivets 8| being passed through the apertures to secure the parts together and clamp inlet pipe 8D and the various liners in position. When the parts are thus brought together, the gland nut 54 is screwed home to the position shown in Figure 4 and the motor is ready for operation, the upper threaded end of stud being securable to any mechanism to be reciprocated. Part II has a neck portion i1' complemental to neck portion I1 of part I2 and these may be externally threaded as shown in Figure 4. For the support of the motor the neck may be passed through an aperture in a supporting plate as at 82 and a nut 83 screwed on the neck to clamp the plate between it and an abutment shoulder S4 at the base of the neck.

It will be understood that to make the casing watertight the contacting faces of the several parts may be painted or suitable gaskets may be provided.

vAssuming the casing to be assembled and pipe 80 to be connected to a source of fluid pressure such as a house water system, the power piston, Figure 4, is near the end of its down stroke, fluid under pressure entering the top of the cylinder through groove 29, the control valve and gro-ove 25, the lower end of the main cylinder being connected through groove 2I, the control Valve and grooves 23 and 23 into the exhaust pocket for discharge through pipe 15. Just before the power piston reaches the bottom of its stroke, the lower end of stud 55 abuts the upper end of stem 58 and moves the pilot valve piston to its lower position. Hereupon fluid under pressure in groove 45 is directed by the pilot valve through groove 42 into recess 33 at the top of piston 52 so that the latter is moved downwardly, the fluid beneath piston 62 being led to the discharge pocket through groove 4I, the pilot valve and grooves 43 and 43. The control valve, being moved to its lower limit, throws the supply into groove ZI so that the power piston is forced upwardly, the uid at the top of the piston exhausting through groove 20, the control valve and grooves 22 and 22. As the power piston nears the top of its stroke, nut 58 abuts nut 59 and the pilot piston is returned to the position shown in Figure 4 so that iuid under pressure is led to the lower side of piston 62 through groove 45, the pilot valve and groove 4I, piston 62 being thus moved upwardly and returned to the position shown in Figure 4. Fluid above piston 62 is exhausted through conduit 42, the pilot valve and grooves 44 and 44. The power piston due to the movement of the control valve is again caused to move downwardly and the sequence is repeated.

When the power piston is operated at full str-oke, the nuts 49 and 50 cooperate with the ends of chamber I3, I3 as stops. However, positive limiting means are not necessary and in fact do not exist if the stroke of the piston is shortened. This can be done by appropriately adjusting nut 59 and stud 55.

Firm frictional contact of packing element 62 with stem 58 should be sucient to hold the latter in adjusted position against gravity and the action of the pressure fluid on the upper end of stem 58. Auxiliary means for maintaining the stem in its adjusted position may of course be provided if desired. It will be remembered that grooves 43 and 44 both communicate with the exhaust chamber so that each is subjected to the pressure existing in the latter.

In Figure 5 I have shown a modied packing arrangement for the piston rod 5I. ccording to this ligure the neck 85 is provided internally with an annular rib 85 which surrounds the piston rod with a close running t. Rib 85 is provided with an annular groove 81 which through a bleed groove 88 is in communication with exhaust recess 22. Above rib 36 is a packing 89 adapted to be compressed by a gland nut 90. An externally conical packing washer 9| is retained between the lower side of rib 85 and a ledge 92, the tip of packing SI being readily compressible so that pressure in the upper end of the power cylinder will cause the tip to engage the piston rod closely around the latter. The base .of the packing member SI is preferably somewhat spaced from the piston rod as shown in Figure 5 in order to enhance the compressibility of the tip and to minimize friction.

From the above it will be evident that I have provided a fluid pressure motor of simplified construction wherein each casing part is adapted to be made by a simple die casting process and all the parts readily assembled into a compact whole, this compactness being attributable to a considerable extent to the use of the ribbon-like passages as particularly shown in Figures 2 and 6. It will be understood that variation may be made from the detailed construction shown and described without departure from the scope of the invention, and accordingly I do not limit myself except as in the following claims.

I claim:

l. In a fluid pressure motor, a casing comprising complemental parts dening conjointly power and control chambers and uid passages operatively connecting said chambers, the arrangement being such that the passages do not cross each other and that each of said parts and the portions of the chambers and passages therein are enabled to be formed completely in a single die casting operation, tubular liners for said chambers clamped between said parts, and means engaging the liners to hold them positively against axial displacement.

2. In a iiuid pressure motor, a casing comprising complemental parts dening conjointjly cylindrical power and control chambers having their axes in a common plane between the parts and so arranged that they do not cross each other, said parts also defining conjointly fluid passages operatively connecting said chambers, each of said parts and the portions of chambers and passages therein'being producible in a single die casting operation, and tubular liners for said chambers clamped between said parts.

3. In a iiuid pressure motor, a casing, a power piston reciprocable in a cylinder in said casing, a control piston reciprocable in a cylinder in said casing tocontrol the fluidrsupply to and exhaust from the power cylinder, an actuating piston for said control piston reciprocable in a cylinder in said casing, a pilot piston reciprocable in a cylinder in said casing to control iiuid supply to and exhaust from said actuating piston and cylinder, and a control connection between the power piston and pilot piston, the axis of each piston being parallel to a line parallel to the axes of the other pistons, and all of said axes lying substantially in av common plane, the casing being split in said plane and having nonerossing supply and exhaust passages defined between its parts and each of said cylinders being constituted by a liner clamped between the casing parts. 4. In a fluid pressure motor, a casing, a power piston reciprocable in a cylinder in said casing, a control piston reciprocable in a cylinder in said casing to control the fluid supply to and exhaust from the power cylinder, an actuating piston for said control piston reciprocable in a cylinder in said casing, a pilot piston reciprocable in a cylinder in said casing to control fluid supply to and exhaust from said actuating piston and cylinder, and a control connection between the power piston and pilot piston, the axes of all of saidl pistons lying substantially in a common plane, the casing being split in said plane and having noncrossing supply and exhaust passages dened between its parts and each of said cylinders being constituted by a liner clamped between the casing parts.

5. In a fluid pressure motor, a split casing whose parts define conjointly chambers for the reception of main and auxiliary driven elements, the casing split being disposed so that the casing parts may be brought together to enclose said driven elements in the respective chambers, said parts also defining conjointly fluid passages operatively connecting said chambers the arrangement being such that the passages do not cross each other and that each of said parts and the portions of the chambers and passages therein are enabled to be formed completely in a single die casting operation, and cylinder liners in said chambers clamped between the casing parts.

6. In a iiuid pressure motor, a casing comprising complemental parts defining conjointly power and control chambers and fluid passages operatively connecting said chambers, said fluid passages being constituted by relatively narrow and relatively deep grooves in one part registering with similar grooves in a complemental part, the arrangement being such that the passages do not cross each other and that each of said parts and the portions of the chambers and passages therein are enabled to be formed completely in a single die casting operation, and cylinder liners in said chambers clamped between the casing parts. Y

'7. In a fluid pressure motor, a casing comprising complemental partsV having registering recesses in their adjacent faces; said recesses when the parts are brought together forming a main power chamber, a control chamber, an auxiliary power chamber in alignment with said control chamber, a pilot chamber and inlet and outlet passages for said chambers; a liner in each of said chambers, means securing the casing parts together Vwhereby said liners are clamped in position, power pistons reciprocable in the liners in said power chambers respectively, double valve pistons reciprocable in said liners in said control and pilot chambers respectively, each of said last named liners being provided medially with a slot registering with an inlet passage therefor and adjacent its ends with slots registering with outlet passages therefor, there being other outlet passages in communication with the ends of said -last named liners respectively, a

connection between the main power piston andV the pilot piston whereby the latter is operated to control fluid flow to and escape from the auxiliary pow-er chamber, and a connection between the auxiliary power piston .and the control piston whereby the latter is operated to control fluid flow to and escape from the main piston chamber, all of said passages being in non-crossing relation to each other and each of the casing parts with its recesses being producible in a single die casting operation.

GEORGE KUHIN. 

